Nichols called the glitch a combination of a computer and human error.

"It is human in that no one caught it as a payroll matter. All payroll is generated by computer and spot checks did not reveal an issue," Nichols said. "For not catching it sooner, I'm very sorry."

Staunton teacher pay has been frozen for three years, but raises totaling more than $16,000 were mistakenly given to those 31 teachers.

All the affected teachers had previously worked at Dixon Elementary School and were reassigned to other schools after Dixon closed two years ago.

The salary increases ranged from $140 to $800 or $900, Nichols told the News Leader.

The superintendent initially said the teachers would not have to repay the money and would forego a future raise instead, when the current pay freeze ends. But the school board decided the teachers should repay the money over the next 24 months.